A video from YouTube channel ML Studios has been making the rounds yesterday, and it was to do with the subject of a fuel’s RON rating and what the effects of using the ‘wrong’ type of RON rating might be for any given type of petrol engine. It starts out promising.
About a minute into this video, presenter Mas Faiz Hakim starts to discuss the correlation between a vehicle’s engine capacity and the RON rating of the petrol used. The presenter says that lower RON fuels are more suited to smaller displacement engines, while engines of larger capacities should be fed higher RON fuels.
Faiz elaborated by saying that using higher RON petrol in a relatively small engine will require it to ‘work twice as hard’, causing it to be over-exerted and eventually require repairs of servicing ahead of schedule. Conversely he adds that a lower RON petrol used in a larger discplacement engine – such as 2.0 litres and above – will cause premature combustion, more commonly known as knocking.
While it is correct that the lower the RON rating, the more easily the petrol will combust, it would be inaccurate to draw a correlation between a fuel’s RON rating and the capacity of engine it is used in. The Research Octane Number, which is what RON stands for, refers to the fuel’s ability to resist premature ignition, which is when the fuel-air mixture combusts upon compression before spark is initiated.
When premature combustion, or knocking occurs, this is manifested as an unusual tapping sound from the engine, hence the term. This is due to a number of factors; once of which could be the presence of excess carbon deposits, which ignites in the combustion chamber and sets off the rest of the air-fuel mixture earlier than it should in the compression stroke.
Another reason knocking can occur is when a lower RON petrol is used in an engine with a high compression ratio operating at fixed parameters – more on this later – and it is this factor rather than the engine’s displacement that is of greater consequence when observing the outcomes of using different RON ratings.
A small displacement engine does not necessarily use a low compression ratio, and similarly a larger engine won’t always have a higher compression ratio than that of the smaller engine. So then, which kinds of engines tend to use higher compression ratios? These will typically be naturally aspirated engines – without forced induction such as exhaust-driven turbochargers or mechanical superchargers.
For instance, the 107 hp/150 Nm 1.6 litre S4PH VVT engine in the 2019 Proton Persona uses a compression ratio of 10:1, while the 185 hp/163 Nm 1.6 litre B16B DOHC VTEC engine in the EK9 Honda Civic Type R has a compression ratio of 10.8:1. Generally speaking, a higher compression ratio enables more power to be extracted from a given capacity, though this also generates more heat.
In the case of the EK9 Type R, the Honda also benefits from lighter – therefore also more expensive – engine internals for a higher RPM limit. These are often partnered with parts such as a more efficient cooling system and the use of more durable materials, which compounds the additional cost and inherently limits their application to more specialist, high-performance vehicles.
On the other hand, forced induction engines such as the 227 hp/350 Nm 2.0 litre TSI turbocharged engine in the Volkswagen Golf GTI uses a compression ratio of just 9.6:1, as the positive pressure or boost has already compressed the intake air, and therefore the air-fuel mixture before the compression stroke.
Back to NA engines – what happens when an engine with a relatively low compression ratio uses a higher RON petrol? Our colleagues Farid (who authored the BM story on this topic) and Durrani from paultan.org/bm carried out this exact test, with a pair of 1.3 litre Proton Sagas with CVT gearboxes. In short, the exercise found that the RON 97-fuelled car actually used slightly more fuel than the RON 95 car, though RON 97 isn’t actually detrimental to the engine’s health.
On the flipside, what if lower RON petrol is used in a high-compression ratio engine, such as the 1.5 litre Skyactiv-G with a 14:1 ratio in the Mazda 2? This isn’t a worry in modern engines with electronic fuel and ignition management as well as knock sensors. If lower than ideal RON petrol is detected via the knock sensors, engine management will adjust ignition accordingly (either advance or retard, based on conditions) to counteract knocking and prevent damage as a result.
In that instance, overall engine output will also be reduced, which leads to the misconception that higher RON petrols ‘give more power’ – what higher RON petrols do is enable high compression ratio engines to perform closer to its potential than a lower RON petrol can, all other factors constant. Gains are there for the taking, though this is from reduced losses.
Perhaps closer attention is also in order; Faiz points out an excerpt in the Perodua Axia manual which states “use only unleaded fuel with it’s Research Octane Number 95 or higher”, which is immediately followed by ‘guna (RON) 95 sahaja, kerana itu yang direka khas untuk kereta jenis Axia’ (“use RON 95 only as that is what the Axia is designed for.”)
Again and as mentioned earlier, higher RON petrol isn’t actually bad for your car, it just may not make financial sense for everyday applications, and the Axia manual did not state RON 95 as a maximum allowed number. The presenter is however, correct in advising users to consult the owner’s manual for correct operation.
Now, what if you’re willing to pay the premium for even higher-rated petrol, namely, RON 100? We’ve put Petron’s Blaze100 to the test against its Blaze95 rangemate, sampled with cars and bikes collectively spanning several segments and employing rolling roads for good, objective measure. Watch the video below to find out more.
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This faiz guy must be having a small displacement brain trying twice as hard to explain a higher RON subject which eventually exposing his premature combustion as a result of knocking on his head.
This is the type of people that gives confusing information to everyone.. Just recently Paultan.org post a video regarding this issue.
Kudos to LGE for RM2.08 Ron95… hidup Msia.
This is talking about Rm2.53 RON97. Take your ministry paid bootlicking elsewhere.
Most people fill up with Ron 95 because our kind Government has given us RM2.08 petrol. If follow previous regime today Ron 95 will be RM4.50
So, let us forget Ron 97. Waste of money.
Toyota engine can tahan anything but Campro engine is kaput wei
True bro..campro kaput..
The only thing kaput is the common sense of P2 trolls. They still thinking PT readers will get fooled by their name-changing, dupe-replying antics. Oh, please grow up.
Please make blog post about calya facelift. press release available on toyota Indonesia website.
Campro worse. I use Ron 97 on my Campro, got knocking sound and jerking. Lousy engine
Where were u sleeping. The Campro engine was introduced in 2004. Back then there was only RON97 for use until RON95 replaces RON92 back in 2009.
Is the guy a mathematician who tried his best to explain about SI-ICE ?
More likely which Axia owner would actually fuel up with RON97 or above?
I guess you haven’t seen modenas kriss fuelling up with ron 97.
Hey, i’ve been fuelling my old legend honda c90 and ex5 with ron 97, takda masalah pun.
How many does that? Don’t just go quoting the very minority as the whole truth.
No surprise when a tidy looking kapchai filling up with RON97. Its cheap to tuned their engine to the max till it can only run properly on 97. Its normal and can be understand by those whom knows just from how the bike sound. If a beat up kapchai is filling with 97 then its done to grab attention at the petrol station…hahahah.
On cars….still got people with normal engine filling up 97. Its easier to their brain to accept what people says rather than researching it themselves.
Dont be surprise there are still some whom claimed our RON95 still got lead in them….lots of lead.
Kapcais at 80-100kmh run at engine speed of between 6,000-8,000rpm and knocking can occur easily especially on hot days. Using 97 can fix this issue and the difference on full tank is a matter of rm2-3 only.
Don’t talk or write without using brain.
I’m answering his question about axia using ron97. It means that there’s no problem for axia to use ron97. Don’t reply without using your brain.
My storekeeper fren fuel up his ex-5 wif ron 97 he said better.
Most car drivers don’t pay attention to motorcylists.
Ha ha, my Kriss only drinks ron97… infact, all my cars & bikes.
We’re talking about Axia owners here. Keep things relevant.
I used to sell AVGAS (left over), piston engine aircraft to Mat Rempit…. that was 9 years ago haha
Why Axia owners will have more riskier when comes pumping RON97 for new Axia because Perodua is an association of manufacturers or suppliers with the purpose of maintaining prices at a high level and restricting competition as well as Perodua doesnt allow Proton to be at the top, only Perodua is only wanted itself to be at the top which is very selfish, highly offensive, snobbish, awful and disrespectful to other car brands. Lastly don’t buy Perodua and also hopefully Perodua sales will keep on dropping
Doesn’t it depend on the minimum ron rating of the engine? If it’s higher than that, there shouldn’t be any problems, but for a small economical engine, it would lose a slight performance, but still won’t make much difference. In other countries, ron95 is very premium
It’s very premium and it’s at least Euro 5.
Poorly written article, I know the facts but I still don’t get what is his point about it.
Axia can explode any time, good luck.
The game changer axia suv body kit
The manual said use only unleaded fuel with ron95 or higher. Not use only ron95
The YouTuber is an idiot
I think you are missing a very important point here. RON 95 is a lot more polluting than RON 97. It will be very beneficial if you can do an article on this rather than performance based. The videos you see on Youtube doing all these tests are based Euro 5 and above petrol of different RON #. It’s more than performance when testing with our local petrol types. Cheap doesn’t mean good all the time.
Boleh-Landers only can understand RON. They can’t seem to comprehend Euro emissions standards, esp when coupled to the RON rating.
It’s akin to multitasking. The brain can multitask RON in relation to Euro rating. It’s a by product of the spoon fed education system.
* can’t multitask …
(damn autocorrect)
A little knowledge is dangerous.
Add R&R, it’s explosive
Malaysians will believe anything. Like the comparo video by some untrained fellow to gauge fuel efficiency of a Bezza vs a Saga. No lab conditions here. Just trust that he drove the same style for both separate journeys from Johor to Selangor.
Granted the Saga may be less efficient, but the test was so unscientific, it would make Britney look like an Ivy League graduate…
2015 ~ 2018, Malaysia crude oil production about 750 Thousand Barrels Per Day.
2015 ~ 2016, Malaysia crude oil consumption about 700 Thousand Barrels Per Day.
Info from America Gov website.
Petroliam Nasional Berhad Untung Manyak Wang :p
2009 trends:
Every monkey with a DSLR thinks he is a professional photographer…
2019 trends:
Every monkey with a Youtube channel thinks he is an expert…
pakai jelah. rosak repair
Well, at least they didn’t hide their sub count of 230k++… ;-)
almost every driver has his or her own formulation and ways to determine which gas suits better and i think this is the best way method. anything else, its just opinion and shouldn’t be debated on.
ntl, there are individuals who are constantly looking or should i say ‘Googling’ for a definite answer.
bottomline, it doesn’t matter if ur willing to pay for a premium fuel in ur Axia, I hate to repeat but as PT have mentioned, they are fuel injected and it shouldn’t matter as long as the Ron rating meets manufacturer’s recommended minimum.
What should be highlighted is the Euro standards instead! Ron97 runs cleaner as compared to Ron95 for obvious reason. PERIOD! Depending on individuals, whether you’re more environmentally conscious or budget bound, by all means, fill in whichever fuel suits u.
Bear in my mind, i’m referring to Malaysian sold brand new cars only, not grey imports where their fuel requirements differs slightly or more.
PEACE.
“Ron97 runs cleaner as compared to Ron95 for obvious reason”
For what reason?
Ron97 is Euro4 while Ron95 is Euro2, Mohd.
Tried n tested by myself. Not gonna pass out the lengthy story but all I can say, for a small displacement engine, it doesn’t matter whether ur running either fuel. Any differences would be insignifcant but what’s significant is the reduced amount of carbon build up in the exhaust pipe with Euro4 fuel.
Personally, I don’t see the fuss for small displacement car drivers over choosing Ron95 or Ron97. Like I mentioned, its a matter of ur own personal preferences made up by ur own personal factors n thoughts.
Ron97 is Euro4M, RON95 is Euro2M
“The presenter says that lower RON fuels are more suited to smaller displacement engines, while engines of larger capacities should be fed higher RON fuels.”
I never heard such a nonsense. 7 liter V8 engines from the US run on very low RON fuel, while small 1.0 turbo engines from Europe require RON97. And 50cc racing eingines require RON100.
True bro.. .
You sure mate? US dont go with RON you know
85 AKI (90 RON) is the minimum octane, and 91 AKI (95 RON) is the maximum octane available in fuel in California.They even don’t have anything similiary like RON97.
With regards to turbos, the (static) compression ratio given by manufacturer doesn’t really represent the ACTUAL compression when the turbine is in operation.
There is a formula for calculating Final Compression Ratio, taking into account the Turbo boost (in psi), static compression ratio and altitude (in feet).
Eg. Proton X70 static compression ratio is 9.6:1. Turbo boost is approx 0.85 bar (12.3 psi) & KL altitude is 66m (216.5 feet)
The ACTUAL Final Compression Ratio thus works out to be 17.56 !! (at max turbo boost of 0.85 bar)
Add in our hot tropicals ambient temperature factor, it would make sense to fuel up with Premium fuel, preferably RON 97 (well, 100 if you afford it long run).
Exactly.
Very informative article PT, keep it up! Just goes to show that there are many viral videos out there with people talking c**k and worst still, many believers.
Just one point though: When knock sensor detects knock, the EMS will retard (not advance) the ignition angle.
What about car with low cc but with turbo? Ron 95 or Ron 97?
Is the a TL;DR version of this article?
Keta bezza nk guna ron95 atau ron97
budak tu nak glamor..biarkanla.bole aje axia pakai minyak ron97.dalam buku mantenan disyorkan pakai minyak ron95 atau
ron lebih tinggi.
Using RON97 on a K-car is just a waste of money.
No harm to the engine whatsoever.
That youtuber in the article, what the heck is he smoking ?